For video encoders, we use Video Swin [1]}, R(2+1)D [2]}, and CLIP4Clip (C4C) [3]}. For Video Swin, we uniformly sample four views of 32 frames with stride 2 in the temporal dimension. For R(2+1)D, we sample every four frames as described in Sec. REF . For C4C, we first extract one frame per second and then uniformly sample a maximum of 100 frames. For Video Swin, we use the official implementation [4]} pretrained on Kinetics-600 [5]}. For R(2+1)D, we use the PyTorch [6]} implementation pretrained on Kinetics-400 [7]}, and for C4C we use the CLIP ViT-B/32 encoder trained on MSR-VTT [8]}.
